JPH0623368A - Method of suppressing contamination of living organism - Google Patents

Abstract

A method for controlling biofouling in aqueous environments which comprises providing ortho-phthalaldehyde to aqueous systems susceptible to biofouling.. The method of the invention is particularly well suited for use in industrial cooling water systems, paper manufacture and in secondary oil recovery processes.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for controlling biofouling in a variety of applications including water treatment, pulp and paper manufacturing and oilfield flooding. More specifically, the present invention relates to a method for controlling biofouling by ortho-phthalaldehyde.

[0002]

BACKGROUND OF THE INVENTION Biological soils are microbial deposits or biofilms (b) on virtually any surface submerged in an aqueous environment.
iofilm) formation. Biofilms are undesired and can cause serious damage in a wide range of industrial systems. In cooling water systems, biofilms reduce the heat transfer coefficient,
Contamination of the tubing and heat exchanger tubing results in significantly increased frictional resistance to liquid pumping and high energy requirements. Secondary oil extraction including waterflooding of oil-bearing formation (s
biofilm is an oil-bearing formation in econdary oil recovery)
(Oil-bearing formation) may be blocked. It is also known that severe corrosion results from the formation of acids associated with the growth of certain bacterial biofilms. These bacterial biofilms consist of sulfate-reducing bacteria that grow anaerobically in water, often in the presence of oil and natural gas.

Biofilms can contain any form of microorganisms, including algae, mushrooms and both aerobic and anaerobic fungi. In addition to these microorganisms, biofilms usually contain extracellular polymeric substances that protect the biofilm from predation and toxins. These macromolecular substances limit the permeability and therefore the microorganisms (sessile microorganisms) contained in or attached to the biofilm are often microorganisms suspended or suspended in the aqueous layer (planktonic properties). It is significantly more difficult to kill with chemical biocides than microorganisms).

A wide range of biocides capable of killing planktonic microorganisms are cited in the literature. See, eg, US Pat. No. 4,297,224. The biocides include oxidative biocides such as chlorine, bromine, chlorine dioxide, chloroisocyanurate and halogen containing hydantoins. The biocides also include non-oxidizing biocides such as quaternary ammonia compounds, isothiazolones, aldehydes, parabens and organic sulfur compounds.

Traditionally, the above biocides have been used to kill planktonic microorganisms in circulating water systems such as cooling water towers and pasteurizers. Until recently, little routine monitoring of biocidal efficacy against sessile microorganisms has been done. Recent studies have reported that various widely used biocides are relatively ineffective against sessile microorganisms. Bacterial Biofilms in Re by Costerton et al., Materials Performace, pp. 49-53 (1988).
lation to Internal Corrosion Monitoring and Biocid
You should refer to e Strategies.

Only a few non-oxidizing biocides have been described as effective in killing sessile microorganisms in established biofilms. The literature lists isothiazolones, formaldehyde and glutaraldehyde as being effective against such sessile microorganisms. Rusesk
et al. reported that isothiazolone was effective in inhibiting biofilm. Oil and Gas Journal, No. 25
Biocide Testing Agains, pages 3-264 (1982)
t Corrosion Causing Oil-Field Bacteria Helps Cont
See rol Plugging. Pope et al. Report that formaldehyde worked well in one test but not another. NAC
E Papers 89-192, National Association of Corros
ion Engineers, Corrosion 1989 Mitigation St
rategies for MicrobiologicallyInfluenced Corrosion
See in Gas Industry Facilities. It has been found that glutaraldehyde is effective in removing biofilm deposits and controlling the number of vegetative microorganisms in a kinetic laboratory reactor simulating water flooding piping conditions. Materials
Performance, Volume 1, pp. 40-45 (1988)
The Use of Gultaraldehyde for Microbial Control
See in Waterflood System. Problems with the current practice include the need to use relatively high concentrations of biocides over extended contact times to kill sessile microorganisms.

Accordingly, there is a need to provide a biocide that is effective against sessile microorganisms and that can be used below the levels at which current biocides are used.

[0008]

SUMMARY OF THE INVENTION The present invention comprises controlling biofouling in an aqueous system comprising providing ortho-phthalaldehyde to the aqueous system in an amount sufficient to kill at least sessile microorganisms contained in the aqueous system. Regarding the method. Ortho-phthalaldehyde is particularly effective in killing sessile microorganisms present in various aqueous environments susceptible to biofouling, and in this regard is much more effective than other biocides reported in the literature. I found out.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Ortho-phthalaldehyde has the formula:

[0010]

[Chemical 1]

And in some cases O herein.
Abbreviated as PA.

In practice OPA is provided in an aqueous system in an "antibacterial effective amount". As used herein, this term refers to the minimum amount of OPA required to substantially kill or inhibit the growth of microorganisms that adhere to at least the walls of the system and other structural surfaces. It is also contemplated in the method of the present invention that OPA is provided to the aqueous system in an amount at least sufficient to inhibit regrowth or growth of the above microorganisms. The specific amount of OPA required depends on the type of adherent microorganism, the contact time between OPA and the microorganism, and the OPA.
Varies with respect to a number of factors, including the aqueous system used.

In general, OPA can be used in the process according to the invention in concentrations of up to about 5% by weight, based on the weight of water in the aqueous system to be treated. However, from the standpoint of efficacy as a biocide against sessile microorganisms, OPA usually contains about 0.5 to about 1000 ppm by weight of water,
Still usually used in small amounts, such as about 5 to about 500 ppm by weight. Usually about 10 to about 250 ppm or less is required. If desired, by using water-miscible cosolvents such as water-miscible glycols, alcohols, furans and ethers, the solubility limit of OPA in water at 25 ° C is exceeded, above about 5% by weight (50,000 ppm). OP
A concentration of A can be achieved. Examples of suitable cosolvents used in the method of the invention are ethylene glycol, methanol, ethanol and tetrahydrofuran.
When a cosolvent is generally used, a high boiling cosolvent such as ethylene glycol is particularly preferred.

Although glutaraldehyde and formaldehyde are the preferred compounds previously disclosed in the prior art for killing or inhibiting the growth of sessile microorganisms, in killing or inhibiting the growth of sessile microorganisms, OPA is one of the above other biocides
It turned out to be much more effective than the seed. However, it should be understood that OPA can be used in the method of the present invention in combination with one or more of glutaraldehyde, formaldehyde or other biocides. Examples of other biocides above are:
Chlorine, bromine, chlorine dioxide, chloroisocyanurate, halogen-containing hydantoin, quaternary ammonium compounds,
Isothiazolones, parabens and organic sulfur compounds.

The aqueous system treated by the method of the present invention is a system in which sessile microorganisms can grow. Such systems may contain a wide range of sessile microorganisms including bacteria, yeasts, mushrooms, molds and algae. It should be understood that the sessile microbial-containing system treated by the method of the present invention may, and often does, also contain planktonic microorganisms.

Rapid killing of microorganisms is particularly important in industrial processes where the contact between the biocide and the microorganisms is relatively short. Examples of such methods include: (1) A portion of the water is periodically lost or removed and replaced with fresh water, which results in the biocide being lost within hours of its addition. (2) Oilfield flooding where biocides are used in "once-through"mode; and (3) Conveyor lubricant. Such systems have contact times of less than 4 hours.

In addition to the rate of biocidal activity, the extent of biocidal activity under prolonged contact is also important in many methods. Examples include (1) control of biofouling in recirculating industrial aqueous fluids such as metal working fluids or heat transfer fluids; and (2) microorganisms in closed loop aqueous systems such as air conditioning, air scrubbers or quench water systems. Killing;

The following examples are provided to illustrate the invention but are not intended to unduly limit the invention. Unless otherwise specified, all parts and percentages are by weight.

The following symbols used in the examples and elsewhere in the specification have the following meanings. ml-ml mm-millimeter mMole-mmol ID-inner diameter OD-outer diameter g-gram oz-ounce ppm-parts per million parts of water GA-glutaraldehyde FA-formaldehyde TGE-tryptone glucose extract SRB-sulfuric acid Salt-reducing bacteria

The following procedure was used to culture the various types of microorganisms used in the examples.

[0021] Stainless steel penicylinde
Growth of aerobic biofilm on r) -Procedure A In a sterile Petri dish (15 x 100 mm), add about 20 ml of sterile Bacto (B).
acto) TGE broth (Difco Labs) was added. To this medium was added 10 ml of a 24-hour culture of the aerobic organism to be tested. Then sterile stainless steel penicillin pillars (outer diameter
10 mm, inner diameter 7 mm, length 10 mm) were placed in the inoculated medium. The cylinder column was placed in the dish either on-end or on-side. The Petri dish containing the penicillin column was then placed at 37 ° C for 48 hours.
Cultivated over time. At that point, the cylinders were individually aseptically removed using forceps, blotted onto sterile filter paper and washed 3 times by immersion in sterile salt solution. This procedure was used to ensure that only microorganisms that were firmly attached in the biofilm were tested.

The two biofilm-coated penicillin pillars were then carefully dropped into separate 10 ml tubes containing various concentrations of biocide solution. After 1 and 4 hours of contact, the penicillin column was aseptically transferred to a new tube of TEG broth and vortexed for 30 seconds to remove all adhering organisms. The resulting broth suspension was then serially diluted and then plated using TGE agar for enumeration. 48 at 37 ℃ before plating
Incubated for hours.

Sulfate Reduction on Mild Steel Penicillin Pillars
Growth of fungal biofilm-Procedure B A medium containing SRB was prepared as follows: Bact (B
acto) Sulfate API broth (Difco Labs) 14.5 g and Bacto agar (Difco Labs) 2.0 g were added to 1000 ml distilled water. The solution was heated and stirred until all ingredients were dissolved. 1 of sodium thioglycolate
A% distilled aqueous solution was also prepared. Then both solutions at 121 ° C
Placed in the autoclave for 30 minutes. After cooling, 5 g of the sodium thioglycollate solution were added to the medium mixture.

Mild steel penicillin column (outer diameter 10 mm, inner diameter 7 m
m, length 10 mm) was cleaned by soaking in 0.5% hydrochloric acid for 10 minutes. The penicillin column was then washed 3 times with distilled water and then dried before use.

A 4 ounce screw-capped bottle was purged with argon to remove oxygen, capped, and then placed in an autoclave. After cooling, add 100 ml of sterile SRB medium to this bottle.
Was added. The cleaned penicillin columns were then added with 10 ml of SRB culture for 5 days. All operations were carried out under a constant flow of argon to minimize oxygen levels. The bottles were then incubated at 37 ° C for 7-14 days (depending on the SRB used). At that point, the penicillin pillars were aseptically removed individually using forceps and blotted with sterile filter paper.

Two biofilm-coated penicillin columns were then added dropwise to 10 ml test tubes of various concentrations of deaerated biocide solution. All biocide and control solutions were nonionic nonylphenol ethoxylate surfactants [TERGITOL ™ NP-4, Union Carbide Chemicals and Plastics, Danbury, O.
K). After the contact time of 1 hour and 4 hours, the penicillin column was taken out and blotted with a sterile filter paper.
RB glass bottle (C & S, Laboratories, Tulsa, O
K) inside. The glass bottle was then sonicated (Bransonic Model 12) for 30 seconds to remove adhered organisms.
The resulting solution was aseptically diluted in additional SRB vials for calculation. Prior to reading, place the vial at 37 ° C
Grown for 28 days. Vial blackning was used as a growth indicator.

Growth of Plankton Sulfate-Reducing Bacteria-Procedure C Stock culture of SRB to be tested.
e) was grown in a commercial SRB vial for 4 days. The vial was then purged with argon for about 30 seconds to remove excess hydrogen sulfide. At that time, a series of SRB vials were each inoculated with 0.1 ml of this stock culture. These vials were then incubated at 37 ° C for 4 days. Each of these vials was then purged with argon. Appropriate stock solutions of biocide were prepared so that the desired concentration of biocide in each SRB vial was obtained by the addition of 0.1-1.0 ml. 1
After 1 hour and a contact time of 4 hours, a 1 ml aliquot was removed from each vial and poured into a new SRB vial. These vials were then aseptically diluted for calculation.

To minimize error, all biocide concentration / contact time points given below were tested in duplicate and the results averaged. The results are presented as the log reduction of the microorganism compared to a control penicillin column treated similarly, except that no biocide was used.

[0029]

Example 1 Performance on Aerobic Biofilms Aerobic oilfield isolates were used in all aerobic biofilm experiments. This culture was obtained from a flooded oil well in Texas, USA and was poorly identified as containing predominantly Pseudomonas species. Procedure A above
Biofilms were grown according to. Each sample was treated with various concentrations of the biocides shown below and then counted for bacteria after a contact time of 1 and 4 hours. The results are shown below.

[0030]

[Table 1]

Although glutaraldehyde and formaldehyde were previously shown to be effective non-oxidizing biocides against biofilms, OPA is superior to both glutaraldehyde and formaldehyde. Examples are given.

[0032]

Example 2 Performance on Aerobic Biofilms Four aromatic aldehydes were compared to OPA to determine their effect on killing organisms buried in biofilms. The compounds selected were salicylaldehyde (SA); orthovanillin (OVA); 2,3-dihydroxybenzaldehyde (DHB); and 2-carboxybenzaldehyde (CB). These four compounds have been shown to have similar biological properties to OPA against five different planktonic microorganisms by Zbl.Bact.Hyg.I.Abt.O.
Rig.B172, pp. 508-519 (1981).
Rano's The Antimicrobial Activity of Substituted Aro
It is reported in the literature entitled matic Aldehydes. The minimum inhibitor concentration (M
It is expected that SA, OVA and DHB are substantially equivalent to OPA based on IC) and CB is less effective.

[0033]

[Table 2]

Samples of each of the five compounds were tested against sessile microorganisms embedded in the biofilm. Although the biofilm was composed of various microorganisms, it contained primarily Pseudomonas spp. Cultivated using Procedure A.
The number of organisms was counted after 1 and 4 hours of contact. The results are shown below:

[0035]

[Table 3]

This example demonstrates the surprising effect of OPA on sessile microorganisms in biofilms, even when other aldehydes are used at levels four times the concentration of OPA. The results show that the four other related aromatic aldehydes tested have activity comparable to OPA in killing planktonic aerobic organisms. Rehn et al. Especially surprising from the point of view.

[0037]

Example 3 Performance on sessile anaerobic biofilms SRB cultures were obtained from a water flood well in Alaska. The procedure was used to culture the fungus on the walls of steel penicillin posts. Then each sample for 1 hour and 4
Incubation with glutaraldehyde, formaldehyde or OPA over time gave the following results:

[0038]

[Table 4]

As in aerobic biofilm experiments, these data indicate that unexpectedly low concentrations (10 ppm) of OPA are able to completely kill all of the anchored anaerobic organisms contained in the biofilm. Indicates that. A significantly higher concentration of glutaraldehyde or formaldehyde was required to achieve the same level of effect.

[0040]

Example 4 Performance against Plankton Anaerobic Bacteria The same plankton SRB samples used in Example 3 above were cultured according to Procedure C above. Each sample of fungus was treated with various concentrations of OPA and the log reduction in fungus number was recorded in each case.

[0041]

[Table 5]

When comparing the results of Example 3 with those of Example 4, the enhanced efficacy of OPA in killing adherent microorganisms is apparent. The result of Table 5 (Example 4) is 50.
Plankton S at high OPA concentrations such as 0 ppm
RB indicates that it was not completely killed. On the other hand, when used to treat sessile microorganisms as in Example 3, complete sterilization was performed at concentrations as low as 10-500 ppm. The results of Example 3 are surprising because it is generally believed that planktonic cells are easier to kill than the microorganisms contained in the biofilm.

Front Page Continuation (72) Inventor Alan, Bell, Teeth 08807, NJ, USA, Bridgewater, Rolling Knowles Way No. 300 (72) Inventor Jonathan, Radar USA, NJ 08822, Flemington, Old・ Croton Road 195

Claims (10)

[Claims] 1. A method for inhibiting the growth of microorganisms that adhere to the walls and other structural surfaces of the system in an aqueous system, wherein at least a sufficient amount of ortho-phthalaldehyde to substantially kill said microorganisms is used in said aqueous system. The above method comprising feeding the system. 2. The method of claim 1 wherein ortho-phthalaldehyde is provided to the aqueous system in an amount of about 0.5 to about 1000 ppm. 3. The method of claim 1 wherein a sufficient amount of ortho-phthalaldehyde is maintained in the aqueous system to inhibit microbial regrowth. 4. The method of claim 1, wherein the aqueous system further comprises planktonic microorganisms. 5. In a method of inhibiting the growth of microorganisms that adhere to the walls and other structural surfaces of the system in an aqueous system, at least an amount of ortho-phthalaldehyde and another amount sufficient to substantially kill said microorganisms. The method comprising providing a biocide to the system. 6. The method of claim 5 wherein the another biocide is selected from the group consisting of glutaraldehyde and formaldehyde. 7. In a method for suppressing the growth of microorganisms that adhere to the wall surface of a system and other structural surfaces in an aqueous system, at least a sufficient amount of ortho-phthalaldehyde to suppress the growth of adherent microorganisms is used in the aqueous solution. The above method comprising feeding the system. 8. The method of claim 7, wherein the aqueous system is a recirculation cooling tower or an oilfield waterflood system. 9. A method for inhibiting the growth of microorganisms that adhere to the wall and other structural surfaces of the system in an aqueous system, the method comprising at least an amount of ortho-phthalaldehyde and another amount sufficient to inhibit the growth of adherent microorganisms. The above method comprising providing a biocide to said aqueous system. 10. The method of claim 9 wherein the another biocide is selected from the group consisting of formaldehyde and glutaraldehyde.